Re: [PATCH 5/5] vdpasim: vDPA device simulator

[Jason Wang]

On 2020/1/17 äå10:10, Jason Gunthorpe wrote:
> On Fri, Jan 17, 2020 at 05:32:39PM +0800, Jason Wang wrote:
> > On 2020/1/16 äå11:47, Jason Gunthorpe wrote:
> > > On Thu, Jan 16, 2020 at 08:42:31PM +0800, Jason Wang wrote:
> > > > This patch implements a software vDPA networking device. The datapath
> > > > is implemented through vringh and workqueue. The device has an on-chip
> > > > IOMMU which translates IOVA to PA. For kernel virtio drivers, vDPA
> > > > simulator driver provides dma_ops. For vhost driers, set_map() methods
> > > > of vdpa_config_ops is implemented to accept mappings from vhost.
> > > >
> > > > A sysfs based management interface is implemented, devices are
> > > > created and removed through:
> > > >
> > > > /sys/devices/virtual/vdpa_simulator/netdev/{create|remove}
> > > This is very gross, creating a class just to get a create/remove and
> > > then not using the class for anything else? Yuk.
> >
> > It includes more information, e.g the devices and the link from vdpa_sim
> > device and vdpa device.
> I feel like regardless of how the device is created there should be a
> consistent virtio centric management for post-creation tasks, such as
> introspection and destruction


Right, actually, this is something that could be done by sysfs as well. 
Having an intermediate steps as "activate" and introducing attributes 
for post-creation tasks.


> A virto struct device should already have back pointers to it's parent
> device, which should be enough to discover the vdpa_sim, none of the
> extra sysfs munging should be needed.
>
> > > > Netlink based lifecycle management could be implemented for vDPA
> > > > simulator as well.
> > > This is just begging for a netlink based approach.
> > >
> > > Certainly netlink driven removal should be an agreeable standard for
> > > all devices, I think.
> >
> > Well, I think Parav had some proposals during the discussion of mdev
> > approach. But I'm not sure if he had any RFC codes for me to integrate it
> > into vdpasim.
> >
> > Or do you want me to propose the netlink API? If yes, would you prefer to a
> > new virtio dedicated one or be a subset of devlink?
> Well, lets see what feed back Parav has
>
> Jason


Ok.

Thanks